ONE skyscraper - Seven World Trade Center - is New York's sole triumph over 9/11. It's a stunning piece of work. Who built Seven? Not Gov. Pataki or Mayor Bloomberg, but private-sector developer Larry Silverstein, who completed the 52-story tower while the pols dithered over 16 scarred acres across the street.

Silverstein could build Seven so quickly - replacing the office building of the same name he owned before 9/11 - because it's adjacent to the World Trade Center site, not part of it. Thus, Silverstein's lease with the Port Authority of New York and New Jersey, the bistate entity that owns Ground Zero, doesn't govern the site. Free from the government "direction" that has overseen Ground Zero redevelopment, Silverstein did what he does best: He built.

In doing so, he proved, as if it needed proving, that private-sector ingenuity can solve difficult problems.

Silverstein had to build 7 WTC around a new Con Ed substation, to replace one destroyed on 9/11. Naysayers said that Seven would thus be a windowless box at street level, unfriendly to pedestrians. Undeterred, Silverstein's architect, David Childs, encased the substation in an elegant stainless-steel shell that complements the glass skyscraper above, and covered it with a delicate light show that will draw pedestrians' glance. It works.

Silverstein built Seven on spec, with no prospective tenants except himself. Lenders ran the risk that his optimism about downtown wouldn't pan out. (The Liberty Bonds that Congress authorized to speed Lower Manhattan's recovery provided most of Seven's financing, but the government doesn't guarantee those bonds; they're merely tax-exempt.)

The critics gave plenty of reasons why Silverstein's optimism was foolish. Nobody wants to work Downtown anymore, they said. Post-9/11, nobody will go up in the sky in a building called the World Trade Center.

Guess what? Silverstein quickly found a tenant for Seven's top five floors. Altogether, tenants will occupy 20 percent of the tower when it opens in May, paying more than $50 per square foot, the highest rate Downtown.

Seven WTC does have drawbacks. It boasts spectacular views - views that disappeared after 9/11 until today. But one is of Fiterman Hall, a City University building that burning debris half destroyed on 9/11, and the city and state have allowed to fester. Every time it rains, mold further contaminates the building. Another view is of the old Deutsche Bank tower, also contaminated on 9/11; the state's responsible for razing it, but it still stands. A third view is of Ground Zero.

But looking straight down at Ground Zero from the top floor of Seven, it's possible to view it not just as a sad reminder of New York's political incompetence in rebuilding from 9/11 but as a construction site and the anchor of a 21st-century neighborhood.

From Seven's top floor, one can see all of Downtown's real estate - and much of it is old. Besides Seven, the World Financial Center provides much of Lower Manhattan's modern office space. But when the rest of the new WTC towers finally rise, the WFC will be 35 years old. Many Downtown office buildings are fast becoming obsolete as office space; owners are converting them into condos.

It's good that Downtown is no longer just a business district. But it's bad for New York's growth if new office towers don't replace the ones disappearing from the market.

Other than Seven World Trade Center, tenants forced out of obsolescent space Downtown have three choices: high-priced Midtown, the World Financial Center (far from transportation) and New Jersey. Once Ground Zero's four modern office towers are done, they'll have another choice: Midtown-style towers close to mass transit.

By finishing Seven, Silverstein has replaced with hope the dread that infused Lower Manhattan after 9/11. Yet pols and the press condemn him - because he's in the private, not the public, sector.

When negotiations over a revised lease down in March, Port Authority vice chairman Charles Gargano called Silverstein "greedy." Pataki said Silverstein had "betrayed the public trust." The New York Times ran an editorial called "Greed vs. Good at Ground Zero," castigating Silverstein for failing to "think beyond the . . . bottom line here."

Gargano and Pataki should be ashamed of their slander of Silverstein, who has been nothing but patient as they and Mayor Bloomberg have turned Ground Zero into a political swamp.

As for the Times: Of course Silverstein must think of the bottom line. If he doesn't earn money, he can't build more breathtaking buildings like Seven. That's how the private sector works. The Times fails to explain why it is bad for New York that Silverstein actually wants what goes up at Ground Zero to succeed.

When the critics aren't condemning Silverstein, they're deriding his optimism about Downtown. But they should remember: When the new World Trade Center is finished, nearly 20 years will have elapsed since 9/11. Manhattan's workforce is an army of young people. To workers in their 20s and 30s in 2020 and beyond, 9/11 will be something that happened in childhood - or in history. The remote horrors of that day will take a backseat to spectacular views.

It's past time for pols who use 9/11 to increase their power over the city's private-sector future to get out of the way, so that this future can take shape.